In mobile communication which has become widespread toady, communication with high accuracy is required in various channel environments. Further, as a means to realize communication with high accuracy even in severe channel environments, error correction encoding processing is performed on transmission data.
In 3GPP (see Non-Patent Literature 1), a plurality of fixed information Hocks formed with a predetermined number of bits K are formed from a series of transmission sequences, and error correction encoding processing is performed per this fixed information block. There is no problem when that series of transmission data sequences can be divided by K. In contrast to this, when that series of transmission data sequences cannot be divided by K, bit padding is performed on that series of transmission data sequences to arrange padding bits in the head part of that series of transmission data sequences, so that the total number of bits is made a number that can be divided by K. Then, encoding processing is performed on the data sequences in which padding bits are arranged, per fixed information block. By this means, it is possible to perform encoding processing of constraint length K uniformly.
Further, error correction encoding schemes include convolutional encoding scheme (for example, see Patent Literature 1) and turbo encoding scheme (for example, see Non-Patent Literature 2).
Then, modulation processing is performed on the codewords obtained by error correction encoding processing in modulation section. A constituent bit group that forms a symbol that is obtained by m-ary modulation can be divided into groups according to BER characteristics based on the constellation (for example, see Patent Literature 2). For example, when gray-coded constellation is used, in 16 QAM, the first and second bits, out of four constituent bits, show good BER characteristics. Further, in 64 QAM, the first to third bits, out of six constituent bits, show good BER characteristics.